The invention relates to cast a cylinder head of a multicylinder internal combustion engine including a cooling water space delimited by cylinder head bottom-top-and sidewalls. Intake and exhaust passages extend through the cooling water space. Also wells for receiving spark plugs or injectors extend through the cooling water space and are connected to the bottom and top walls of the cylinderhead.
Modern internal combustion engines, particularly highly charged Diesel engines with direct fuel injection are subjected to high peak combustion pressures which requires the cylinder head to have a high rigidity. With insufficient rigidity high vibration amplitudes can occur in the center area of the combustion chambers, which can lead to the formation of cracks in the cylinder head bottom wall and/or in other parts of the cylinder head. In addition, deformations of the valve guides and the valve seals may occur which may result in valve breakages or at least in valve leaks with subsequent thermal overloading of the valves, the valve seat rings and the valve guides.
A cast cylinder head of this type (see for example, DE-A 35 13 126) includes a water space delimited by the cylinder head bottom- top- and sidewalls. Intake and exhaust passages and wells for receiving spark plugs or injectors extend through the cooling water space. To increase the rigidity of the areas of the cylinder head bottom wall in the vicinity of the combustion chambers, the arrangement as shown in DE-A 35 13 126 includes within the cooling water space support walls which extend between the cylinder head bottom and top walls. The support walls have incorporated therein support columns for bores receiving the cylinder head bolts. In addition, there is provided a longitudinal rib, which extends between the cylinder head bottom and top walls over the length of the cylinder head and which is interconnected with the support walls and the wells for the spark plugs or the injectors. In this way, the rigidity of the cylinder head is substantially increased, but this is still not sufficient to accommodate the extremely high peak pressures of Diesel engines with direct fuel injection.
It is therefore the principal object of the present invention to provide a cylinder head with further increased rigidity.